Most water supply systems include a motor driven submersible pump located in a well to supply water to a residence or remote source of demand. To avoid rapid or frequent cycling of the pump motor, as during periods of small water demands, it has been necessary to provide pressure tanks, as separate units, with such water systems. These pressure tanks are usually located above the ground, such as in the basement of a home, in the line between the pump and the demand source.
While there are many types of pressure tanks, all generally perform the function of holding a supply of water under pressure to meet small water demands without the need for the pump to cycle. For example, in a typical tank a diaphragm or bladder separates air under pressure and the water supply. As such, before the pump shuts off at the end of a demand cycle, the lower part of the tank fills with water compressing the air above the bladder at the top of the tank. Then, at the time of a small demand, such as the opening of a faucet for a few moments, the supply of water to meet that demand is provided by the tank, with the air pressure above the bladder forcing the water to the location of the demand. Only when the water in the tank is essentially depleted, either by a series of small demands or upon a large demand, is it necessary for the pump to be activated thereby prolonging the life of the pump and particularly the motor thereof.
While such tanks adequately function for their intended purpose, they are not without their deficiencies. First, they represent significant initial and maintenance costs to the system. In addition, depending on the water system involved, they can be quite sizeable, some models being over six feet tall and two feet in diameter. As such, they take up a great deal of space for the consumer and represent a sizeable shipping cost to the manufacturer. Moreover, pressure tanks in the home represent a potential safety hazard in that the internal pressure, acting against the large surface area of the tanks, creates a significant force. As such, the pressure tanks have been known to fracture or explode, especially after they structurally deteriorate and yet are still exposed to the necessary internal pressures.
Thus, the need exists for a system which can supply small demands without the need for the expensive and potentially hazardous pressure tank.